High-Spin Blatter’s Triradicals

Abstract

Robust organic triradicals with high-spin quartet ground states provide promising applications in molecular magnets, spintronics, etc. In this context, a triradical based on Blatter's radical has been synthesized recently, having two low-lying non-degenerate doublet states with a quartet ground state. The traditional broken-symmetry (BS)-DFT computed doublet−quartet energy gaps are reported to be somewhat overestimated in comparison to the experimentally observed values. In this work, we have employed different ab initio methods on this prototypical system to obtain more accurate doublet−quartet energy gaps for this triradical. The spin-constraint broken-symmetry (CBS)-DFT method has been used to reduce the overestimation of energy gaps from BS-DFT. To address the issues of spin-contamination and the multireference nature of low-spin states affecting the DFT methods, we have computed the energy gaps using appropriately state-averaged CASSCF and NEVPT2 computations. Using a series of active spaces, our calculations are shown to provide quite accurate values in concordance with the experimentally observed results. Furthermore, we have proposed and modeled another two triradicals based on Blatter's radical, which are of interest for experimental synthesis and characterization. Our computations show that all these triradicals also have a quartet ground state with a similar energy difference between the excited doublet states.

A Nitronyl Nitroxide‐Substituted Benzotriazinyl Tetraradical**

“…[18,19] However, their potential use for device fabrication depends not only on their intrinsic electronic properties, but also on stability and processability. [20] A number of kinetically stable radicals, including nitroxide, phenoxide, nitronyl nitroxide (NN), iminonitroxide, and oxoverdazyl radicals, have been known for many years. [21] Another exceptionally stable radical is the 1,2,4-benzotriazinyl radical synthesized by Blatter et al [22] (Blt radical).…”

Orchestration of ferro- and anti-ferromagnetic ordering in gold nanoclusters

“…One of the key strategies to harness the magnetic ordering of the spin-bearing organic as well as inorganic moieties is to use a conjugated molecular framework as a coupler through which the magnetic exchange can be communicated between two spatially separated spin sources. 9–13,71–76 The π electron-rich aromatic organic molecules, such as benzene, are an excellent choice in this context. To exhibit an efficient ordering of magnetic moments, the coupled gold clusters must retain their magnetic properties when they are connected via an organic spacer.…”

A Stable Aluminum Tris(dithiolene) Triradical

“…Significant advances in the chemistry of stable organic diradicals and polyradicals, usually involving carbon, nitrogen, and oxygen elements, have been reported. − Organic di- or polyradicals with high-spin ground states and large energy gaps (Δ E ) between the high-spin ground state and low-spin excited state are intriguing due to their remarkable application potentials in magnetic materials. , Notably, main group element-based polyradicals beyond carbon, nitrogen, and oxygen are scarce. − Since the radical character of the dithiolene ligand in transition-metal complexes was first proposed by Gray et al in the early 1960s, , transition-metal dithiolene complexes with radical dithiolene ligands have received significant attention . Typically, tris­(dithiolene) metal complexes involve three dianionic dithiolate ligands (L 2– ).…”